The present invention pertains to a method and apparatus for implementing unified clipboard memory for use in a keyboard, video and mouse (KVM) switch device. More specifically, the present invention pertains to enabling a selected one of several computers to write to and read from unified memory inside a KVM switch.
The clipboard is typically defined as an area in the computer's memory that functions as a holding place for data that was last cut or copied from a document or file. The data stored on the clipboard can then be inserted (pasted) into other documents and other applications. When data is cut or copied, it is temporarily saved in a portion of system memory commonly referred to as clipboard memory. Subsequently, when the paste command is used, the clipboard memory is accessed to retrieve the data that was last saved on the clipboard and displayed.
Keyboard, video and mouse (KVM) switches are well-known devices that allow multiple computers to share the same keyboard, mouse, and video monitor (commonly known as computer peripherals). KVM switch boxes enable a user to switch access between one of a number of associated computers connected to the box. Typically, each computer is connected to the switch box using standard PS/2 (Personal System 2, IBM technical reference), USB (Universal Serial Bus specification Version 1.0, Jan. 19, 1996) and VGA (Video Graphics Array standard, IBM, 1987) cabling. The keyboard, video and mouse are also attached to connections on the switch box. This allows the peripherals to communicate with any one of the connected computers currently selected regardless of the data protocol used by any of the components connected to the KVM switch box.
A KVM switch box will typically have at least one set of ports for the peripherals to transmit to and receive signals from the switch box. Several sets of computer ports (i.e. interface connections for keyboard, video and mouse) are also made available to connect each of the associated computers to the switch box. A button or knob is placed on the switch box to select which one of the associated computers is currently communicating with the peripherals. Other known embodiments of KVM switches include several sets of ports for additional peripherals or employment of a different switching mechanism and architecture (e.g. allowing for remote switching via keyboard or mouse commands).
KVM switch boxes are used in environments where users need access to multiple computers at the same physical location, allowing users to quickly alternate usage between one of several associated computers while using the same set of peripherals. However, the switch boxes lack the ability to enable the associated computers to directly transfer data to one another.
One solution to transfer clipboard data across two computers has been to cut or copy the content from one document, paste the content into a new document, and transfer the new document to the target computer using removable storage media or over a network. After the file is transferred, the document must be opened, and the user must perform another cut and paste operation in order to get the content to the target document.
In view of the above, there is a need for a method and apparatus for implementing unified clipboard memory over multiple computers.